Antistatic photographic film



P. C. SEEL.

ANTISTATIC PHOTOGRAPHIC FILM. APPLICATION man DEC-31.1920.

1 1,434,454. Patented Nov. 7, 1922.

Phafograp/Y/bn/[y 5 @1751 five La er: 1

)Vr'fmaslidlose Layer Con/airing 0 Sugar;

an Inert hygroscopic Orgaruc Compound and Wafer.

WITNESS INVENTOR ATTORNEY Patented Nov. 7, 1922.

UNITED STATES PATENT OFFICE.

PAUL C. SEEL, OF ROCHESTER, NEW YORK, ASSIGN 'OR TO EASTMAN KODAKCOMPANY, 01 ROCHESTER, NEW YORK, A CORPORATION 01 NEW YORK ANTISTATICPHOTOGRAPHIG FILM.

Application filed December 81, 1920. Serial No. 434,854.

the usual qualities and possessing in addition the property ofpreventing or greatly minimizing markings due to electrical dischargeswhich are customarily referred to 1n the motion picture art as static.Other ob ects will hereinafter appear.

I have found that photographic film may be rendered substantiallyanti-static by incorporating in the nitrocellulose base or supportthereof certain substances together with small amounts of water. Thepreferred substances which -I employ are glucose and glycerin. In placeof the glucose analogous sugary substances ma be employed and in placeof the glycerin may employ similar organic compounds of low volatilitywhich are hygroscopic or have a strong afiinity for water and aresubstantially inert toward the photographic coatings.

- In the accompanying drawing the single figure is a sectional view onan exaggerated scale of a film embodying my invention.

In the drawing 1 is the base or support and 2 the sensitive layer.

In practice I mix the anti-static ingredients together and then add'suchmixture to any of the usual nitrocellulose film dopes, In the preferredembodiment of my invention I add an amount of glucose equal to from 2 to4% of the weight of the nitrocellulose in the dope, an amount ofglycerin equal to from 2 to 4% of the weight of the nitrocellulose inthe dope and an amount of water equal to from 2 to 4% of the weight ofthe nitrocellulose in the dope. f course, these proportions are merelyillustrative and may be varied considerably according to the thicknessof the dope and the methods of 4 and uring the iatter. But the her-2%:-described were As an illustration of the formula to which my anti-staticmixture may be added the following is noted: 100 arts of nitrocellulose,200 to 400 (say 250 parts of acetone, 200 to 400 (say 250) parts ofmethyl alcohol, 20 to 200 (say 40) parts of fusel oil. this may beadded, if desired, 1 to 30 (say 10) parts of camphor; My mixture of 4parts of glucose, 4 parts of glycerin and 4 parts of water is thenincorporated thoroughly in the dope.

The ingredients are those commonly used in the art, of sufficient purityto yield films of the desired transparency and relative freedom fromcolor. Various volatile solvents may be used and either acetone ormethyl alcohol can be used alone in a suitable amount or varyingmixtures can be employed. For the fusel oil may be substituted the othermonohydroxy aliphatic alcohols of from 4 to 5 carbon atoms, like normalbutyl and isobutyl alcohols.

The (lope is spread and cured by the evaporation of the volatilesolvents, so as to form a transparent flexible sheet or film base in theusual way. On this support the sensitive photographic coatings oremulsions are applied and from the product motion picture films andother films are prepared as is well understood in the art. Such filmsare notably resistant to defects from the electrical discharges. While Iam inclined to attribute this propert to the increased electricalconductivity 0 the film base, due to the moisture which is trapped orheld therein by the glucose and glycerin, a knowledge of the theoreticalbasis of my invention is not necemary to the practicing of it, ashereinabovedescribed. It should be noted that the water, whenincorporated with the sub stances and in the manner set forth in theexamples given above, does not segregate in the film so as to impair thetransparency of the latter.

The film base and dope are covered in my co-pending divisionalapplication, Serial No. 461,916, filed Apr. 16, 1921.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent i photogra i i film comprising sensitivecoating on a nitrocellulose support which contains a. sugar, an inerthygroscopic organic compound of low volatility and Water.

2. A photographic film comprising a sensitive coating on anitrocellulose support which contains a sugar glycerin, and water.

3. A photographic film comprising a sensitive coating on anitrocellulose support which contains glucose an inert hygroscopicorganic compound of low volatility and Water.

i. A photographic film comprising a sensitive coating on anitrocellulose support which contains'glucose, glycerin anti Water.

A photographic comprising a sensitive coating on a nitrocellulosesupport which contains an amount a sugar equal to approximately 4% orless of the weight the nitrocellulose, an amount of an inertv Weight ofthe nitrocellulose ancl an aincunt of Water equal to substantially l% orless of the Weight of the nitrocellulose.

'l. A photographic film comprising a sensitive coating on anitrocellulose support Which contains an amount of glucose equal tosubstantially 4% or less elf the w'eight of the nitrocellulose, anamount of an inert hygroscopic' organic compound of low volatility equalto substantial 7 or less of the Weight of the nitroce lulose and anamount of Water equal to substantially 4:92 or less of the Weight of thenitrocellulose.

8. A photographic film comprising a sensitive coating" on anitrocellulose support which contains an amount of glucose. equal tosubstantially. l:% or less of the Weight of the nitrocellulose, anamount of glycerin equal to substantially l% or less oi the Weight ofthe nitrocellulose and an amount of Water equal to sulostan lly 4% orless of the Weight oi the l'lllilOCGll'tliOSG.

9. A photographic film comprising a sensitive coating on anitrocellulose support, which contains water ancl organic material forretaining and preventing precipitation of said Water.

Signed at Rochester, New York, this filth clay or" December, 1920

